Day 10 of 30 Days Wild - Sharow Church sandstone walls - checkup

 Sandstone or limestone walls?

Thursday is a revisit to Sharow to checkup on the walls of the church - are they really made of sandstone?

Yesterday I had been looking at the west facing  wall and - after discussion with the primary school children - noticed the erosion in the sandstone wall of the church.  - erosion which I had not noticed earlier that day when observing the moth trappers emptying the moth trap

view from south - and note yew tree off the left

Yet there is much more erosion in the perimeter churchyard wall.

Quite impressive.  And quite beautiful - natural shapes look beautiful - 

I had assumed the outside wall was very old.

Well it is old - but there seems to be no reason why it is any older than the church - 200 years old.

The erosion is happening under the yew trees.. Also the West wall of the church is near to a yew tree.

So is this variety of sandstone one which includes basic (the opposite of acid) material. 

I scrape of tiny bits of sand from rock and test for the pH. 

The vertical rock is about pH 7.8(centre) the mortar (left) is pH 8 and off the scale and the capstone (right) is more acid at about pH7.3

Looking down on a broken capstone on the perimeter churchyard wall, showing it is made of a similar soft sandstone to the vertical part of the wall.

Elsewhere I have seen a lichen on a wall top and assumed it was an acid loving lichen because was on sandstone.

I now need a name that I do not know to describe an architectural feature: - the sort of  metre tall wainscott round a church

The wall at the base of an old building is wider near the base , the the wall gets a bit thinner a metre up,

Like a wainscott.

And there is a sort of capstone at the top of where this happens. 

 In the Limestone building at Malham Tarn House, this ridge is made out of (acid) sandstone - hence my expectation that this ridge would be acid here.

I went round the back of the church where I had found what I thought was Pertusaria albescens -var coralloides. - the white patches

In the dales I have found my found P albescens var coralloides on sandstone rocks - often in mixed limestone and sandstone walls - had made me assume that the sloping stones were made of an acidic sandstone.. but ..

Pertusaria albescens var coralloides - possibly

A Garden Carpet moth

I looked carefully, the "Sloping" stones were not separate stones at an angle, but just stones carved with the top edge sloping. Some parts of the black had eroded to reveal yellow sandy material inside. The dark colour of the sloping parts was due to the lichen and algal growth and biofilm on them.

This interesting Lecanora was growing there too.

This photo includes part of the new wing with the new toilets

The sandstone walls are so basic I wonder how they  compare with the magnesian limestone at Quarry Moor, 2 miles /SW of Sharow.

The rocks there were laid down in the Zechstein Sea.

That will be tomorrows trip